- add MemoizedSlots, a generalized solution to using __getattr__

for memoization on a class that uses slots.
- apply many more __slots__.  mem use for nova now at 46% savings

1 files changed, 13 insertions, 5 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 445857b82..8df22b7a6 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -3387,7 +3387,7 @@ class ReleaseSavepointClause(_IdentifiedClause):
     __visit_name__ = 'release_savepoint'
 
 
-class quoted_name(util.text_type):
+class quoted_name(util.MemoizedSlots, util.text_type):
     """Represent a SQL identifier combined with quoting preferences.
 
     :class:`.quoted_name` is a Python unicode/str subclass which
@@ -3431,6 +3431,8 @@ class quoted_name(util.text_type):
 
     """
 
+    __slots__ = 'quote', 'lower', 'upper'
+
     def __new__(cls, value, quote):
         if value is None:
             return None
@@ -3450,15 +3452,13 @@ class quoted_name(util.text_type):
     def __reduce__(self):
         return quoted_name, (util.text_type(self), self.quote)
 
-    @util.memoized_instancemethod
-    def lower(self):
+    def _memoized_method_lower(self):
         if self.quote:
             return self
         else:
             return util.text_type(self).lower()
 
-    @util.memoized_instancemethod
-    def upper(self):
+    def _memoized_method_upper(self):
         if self.quote:
             return self
         else:
@@ -3475,6 +3475,8 @@ class _truncated_label(quoted_name):
     """A unicode subclass used to identify symbolic "
     "names that may require truncation."""
 
+    __slots__ = ()
+
     def __new__(cls, value, quote=None):
         quote = getattr(value, "quote", quote)
         # return super(_truncated_label, cls).__new__(cls, value, quote, True)
@@ -3531,6 +3533,7 @@ class conv(_truncated_label):
         :ref:`constraint_naming_conventions`
 
     """
+    __slots__ = ()
 
 
 class _defer_name(_truncated_label):
@@ -3538,6 +3541,8 @@ class _defer_name(_truncated_label):
     generation.
 
     """
+    __slots__ = ()
+
     def __new__(cls, value):
         if value is None:
             return _NONE_NAME
@@ -3552,6 +3557,7 @@ class _defer_name(_truncated_label):
 
 class _defer_none_name(_defer_name):
     """indicate a 'deferred' name that was ultimately the value None."""
+    __slots__ = ()
 
 _NONE_NAME = _defer_none_name("_unnamed_")
 
@@ -3566,6 +3572,8 @@ class _anonymous_label(_truncated_label):
     """A unicode subclass used to identify anonymously
     generated names."""
 
+    __slots__ = ()
+
     def __add__(self, other):
         return _anonymous_label(
             quoted_name(